1. Field of the Invention
The present invention pertains to apparatus for testing properties of materials. In particular, it pertains to apparatus for testing the hardness properties of materials. More specifically, the present invention pertains to mounting apparatus suitable for mounting hardness testers for measuring hardness properties of large flat pieces of non-ferrous materials.
2. Brief Description of the Prior Art
It is frequently necessary to determine certain physical properties and characteristics of materials. This is particularly true in the production of metal goods where a range of properties, such as hardness may be specified or required in the production or fabrication thereof. Hardness, as generally applied to physical properties of materials such as metals, can be measured by determining resistance to penetration. Several scales or standards of reference for hardness of materials have been developed over the years. Two of the most common scales are the Rockwell and Brinell hardness scales.
Various testing methods have been developed to indicate or measure the hardness properties of materials. These hardness testing methods usually measure indentation or penetration of a penetrating device to which predetermined loads are applied. Commonly, the penetrating device, upon clamping of the material to be tested adjacent the tester, is placed against the material with a minor or preliminary load supplied thereto. Then a full or major load is applied to the penetrator. The difference of penetration of material between the minor and major load is measured on a suitable indicator. This measurement then gives an indication of the hardness of the material.
With many testers of the prior art, it is necessary to bring the material being tested to the tester or a work table for clamping therein prior to the test. This is sometimes difficult or impossible depending upon the shape of the material being tested. For example, a large flat plate is difficult to place in a relatively smaller clamping device. In testing tubular goods, clamping may result in inaccurate readings due to deformation of the tested goods.
Because of the problems associated with bringing certain goods to a tester or properly clamping the goods next to the tester, mobile testing apparatus have been developed. Mobile testers may be designed for clamping to the material being tested without the necessity of a permanent or stationary work table. In the previously identified co-pending patent application Serial No. 944,548, a mobile tester is provided with an electromagnet for magnetically attaching the testing apparatus to the material to be tested. Thus, a clamping assembly is not required. This solves the clamping problem in any applications in which the material being tested is ferrous. However, magnetic attachment cannot be used on non-ferrous materials, such as aluminum.